Powdered wax suitable for emulsions and rubber blending

ABSTRACT

Wax powder which is resistant to congealing is prepared by blending molten wax and an antiblocking agent, dispersing the blend, and then cooling the dispersed blend below its melting point to form the powder.

United States Patent Evans et al.

[54] POWDERED WAX SUITABLE FOR 1,

EMULSIONS AND RUBBER BLENDING [72] Inventors: Robert R. Evans,Fullerton; Peter S.

Backlund, Anaheim, both of Calif.

[73] Assignee: Unlon Oll Company 01 California, Los Angeles, Calif.

[22] Filed: Jan. 23, 1967 21 App1.No.: 610,821

[52] US. Cl ..106/270, 106/271, 252/311.5,

[51] Int. Cl. ..C08h 9/08 [58] Field of Search ..106/270, 271, 272;239/102;

[56] References Cited UNITED STATES PATENTS 3,152,917 10/1964 McCoy..l06/27l 3,266,924 8/1966 Haeske ..106/272 Feb. 22, 1972 OTHERPUBLICATIONS Warth Chemistry and Technology of Waxes 1956, Reinhold Pub.Co., pages 487, 488.

Primary Examiner-Morris Liebman Assistant Examiner-P. R. MichlAttorney-Milton W. Lee, Richard C. Hartman, Lannas S. Henderson andRobert E. Strauss [57] ABSTRACT Wax powder which is resistant tocongealing is prepared by blending molten wax and an antiblocking agent,dispersing the blend, and then cooling the dispersed blend below itsmelting point to form the powder.

2 Claims, No Drawings POWDERED WAX SUITABLE FOR EMULSIONS AND RUBBERBLENDING This invention relates to a process for dispersing waxes andmore specifically to a process for producing waxes and wax emulsionssuitable for use in rubber blends and to the composition of the rubberblends with these waxes.

Wax emulsions such as paraffin wax find use in oil-well producingoperations, as paperboard coating and for imparting a waterproof coatingto hard board such as Masonite. Wax emulsions are also used asantioxidents for rubber and also are incorporated into rubber latices asa mold release agent and flame retardant for rubber and foam rubbermoldings. However, there are several drawbacks when using present waxemulsions, particularly in rubber and foam rubber. if the wax emulsionis shipped, rather than being formulated at the point of use, anunnecessary transportation expense is incurred because the emulsioncontains about 50 percent water. Obviously it would be better to shipthe wax in a dry condition and add the water at the point of use;however, the powdered wax used in wax emulsions tends to congeal instorage or even when bulk shipped as a powder.

Another drawback of present wax emulsions having a high (about 60percent) solids content is their lack of long term stability. Thisprevents both the user and manufacturer from maintaining a suitablestockpile on hand. Another drawback of present wax emulsions is theadverse effect some of the wax emulsifiers (e.g., the spans and tweens)have on the rubber foaming process.

With these drawbacks in mind it is an object of the invention to providea powdered paraffin wax which resists congealmg.

Another object is to provide a new and improved powdered paraffin waxblend with rubber or foam rubber.

Another object is to provide a stable dispersion of powdered wax inwater.

Another object is to provide a new and improved process for powderingwaxes.

Other objects will be disclosed from the description to follow.

The objects of the invention are achieved by incorporating anantiblocking agent into the wax prior to or during the powderingprocess. While not essential to the powdering process, the antiblockingagent prevents the wax particles from congealing into larger scaleagglomerates while they are being formed. During storing ortransportation, the natural tendency of the powdered wax to congeal isalso prevented by the action of the antiblocking agent. Furthermore, thewax particles do not undergo a deleterious increase in particle size andconsequently may be incorporated directly into the rubber latex or intoa water emulsion suitable for addition to a rubber latex.

The water emulsion of these powdered waxes may also be employed forcoating articles, waterproofing, oil well producing operations, etc. Theemulsions have long term storage stability even at concentrations of 60percent.

The waxes contemplated by this invention vary in means molecular weightfrom about 550 to 1,000. The waxes at the lower end of the molecularweight range are linear paraffms which occur naturally in crude oil andwhich have been separated therefrom. One particularly preferred type ofwax containing about 45 carbon atoms per molecule and known as Aristowax143/150 is sold by the Union Oil Company of California. The waxes at theupper end of the molecular weight range are of the microcrystallinetype. One such type of wax is sold by the Sunray DX Oil Company, Tulsa,Okla. under the trade name ofSunray DX m 1 60s.

The antiblocking agents which may be employed in this invention arecommonly employed with high molecular weight polymers such aspolyethylene, polypropylene, etc. These antiblocking agents include N,N'-ethylene bis-stearamide (sold by the Carlisle Chemical Company asCarlisle Wax 280), methylene bis-stearamide, polyethylene glycol (about4,000 molecular weight), micronized silica, carnauba wax, sugar cane waxand glokem wax (long chain fatty amide and esters).

Slip agents having antiblocking properties may also be employed as anadditive provided that they impart an antiblocking effect to the wax.Since slip and antiblocking are closely related properties, it ispreferable to employ a compound which is both a slip agent and anantiblocking agent. N, N'ethylene bis-stearamide will perform this dualfunction when employed with Aristowax 143/ l 50.

The concentration of antiblocking agent which is employed will vary,depending on the type of wax employed and on the properties of theantiblocking agent, but is generally less than 0.5 percent. About 0.2percent of N, N'-ethylene bisstearamide, in Aristowax is effective.

EXAMPLE 1 Production of Powdered Wax A quantity of Aristowax 143/150 wasmixed with 0.2 percent N, N-ethylene bis-stearamide (Carlisle Wax 280)and heated to 308 F. to melt the blend. This melting temperature issufficiently in excess (about 50 F.) of the Aristowax melting point toensure a nonviscous flow. The molten mixture was pressured with air andsteam at 300 F. and then ejected at 1.8 pounds per minute from anultrasonic nozzle at a pressure of 84 p.s.i. (Nitrogen, carbon dioxideor any other inert gases may be also employed in place of or inconjunction with air and steam.) This dispersed the molten wax into theair as a powder which immediately cooled to below the meltingtemperature without congealing to form particles having a size of about0.5 to 20 microns. The ultrasonic nozzle employed was manufactured byAstronics, lnc., Syosset, NY. under the trade name of Series 4000Astrospray Nozzle." Nozzles of this type are described in U.S. Pat. Nos.2,5 l 9,6 l 9; 3,08 l ,946; and 3,070,313.

EXAMPLE 2 Trade Nume Chemical Composition Manufacturer Aerosol OT-75Dioctyl sodium sulloccinute American Cyunumid (0. Triton X-l65Alkylphenoxy polyethyuxy ethanols Rohm & Haas (0. Tergitol NPXAlkylphenoxy polyethunols Union Curhidc Tergitol NP33 ethoxy ethanolsChemicals Emcol 230-76 Sodium bis(tridecyl) sulfosuccinate WitcoChemical Co. Emcol T-6O Alkylphenoxy polyethoxy ethanols Witco ChemicalCo.

In general, mixtures of nonionic (alkylphenoxy polyethoxy ethanols) andanionic (sodium sulfosuccinate types) surfactants may be used asemulsifiers.

EXAMPLE 3 Production of Emulsions Containing a High Wax Content: theseare produced using the following formulation:

Composition A (50% solids) Composition B (60% solids) l parts powderedwax of example l 80 parts water 0.4 parts lgepal CO 970 0.4 parts EmcolL30-76 lgepal CO 970 is a surfactant of the nonylphenoxy polyoxyethyleneethanol type, and is sold by the General Dyestuff Corp. Emcol L30-76 isa surfactant of the sodium bis(tridecyl) sulfosuccinate type. Othersurfactants which may be employed are mixtures of nonionic and anionictypes.

Compositions A and B were stable for about 8 hours and could bestabilized for several days by the addition of 0.2 and 0.1 partrespectively of Dow Pusher, a composition of the polyacrylamide type200,00() molecular weight). Equivalent long term stabilized emulsionscan be obtained by employing stabilizers such as hydroxymethyl celluloseand hydroxyethyl cellulose. These compounds are commercially The foamrubber produced from Compounds 1 and 2 above were equivalent in flameretardant properties to that produced using the wax additive, Mobil SerA, a wax sold by Socony M hil lcseesnx.

Many other rubber latices are available such as: butadieneacrylonitrile,natural rubber, polyisoprene rubber, stereoregular polybutadiene, andother synthetic rubber latices.

lt will be observed that Compound 2 of Example 4 is virtually 100percent wax, and this is cheaper and more convenient from the standpointof shipping, since water is not a weight factor. In addition, the pureor emulsified powdered wax containing the antiblocking agent can bestored for about 6 months without the occurrence of deleteriousagglomeration; this permits a suitable inventory to be maintained bothat the site of manufacturing and the site of use. Normally, the storagelife of prior art wax emulsions is about one week.

. 2O available and can be obtained with wide variations in molecuwe iand acetyl i whlch pemms a wlde 1. A process for powdering wax whichcomprises ejecting a 0 en OIyI'fFthaCrYIamIdE m also be employednonviscous solution of an antiblocking agent and a wax to impart longterm stability to the emulsions ofpowdered wax Selected f the groupconsisting f ff w and and water microcrystalline wax through anultrasonic nozzle under fluid The emulslons Stabmzers be mlcorporatedlmothe pressure and cooling the resultant powder below its melting wax atthe powdermg stage and this permits an emulsification poirm simply beadding the wax to the water and stirring.

2. The process of claim 1 in which the concentration of EXAMPLE 4 fantiblockmg agent rs sufficiently high to prevent congea mg 0 Productionof Rubber-Wax Emulsions the wax powder. 1 in which the concentration ofantiblocking The following waxes were incorporated into a rubber latexagent is sufficiently high to prevent congealin g of the wax prior tofoaming to impart flame retardant properties to the powder. foam rubber.

Particle Compound Wax composition size Rubber latex type Concentrationof wax in rubber latex 1 58% emulsion of a 140 F. melting point delaStyrene-butadieno synthetic 2 parts wax emulsion; 98 parts rubber latexoiled paraifin Wax. rubber latex. containing equal parts of:

A: 97.25% water, 1.80% aerosol OT-76,

0.95% Triton X-165, and B: rubber latex.

2 99.8% powdered, de-oiled paraffin wax, 140 1;: Styrene-butadienesynthetic 2% powdered wax (with anti-blocking agent);

F. melting point and powdered by method rubber latex. 98% rubber latexcontaining equal parts of: of claim 1 with 0.2% anti-blocking agent A:97.25% water, 1.80% aerosol OT-75, (Carlisle wax 280). 0.95% TritonX165, and

B: rubber latex.

UNITED STATES PATENT OFFIQE QERTIFICATE 0E QURRECTIGN Patent 3,644,130 Dd February 22 1972 lnventm-(s) Robert R. Evans and Peter S. Backlund Itis certified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Claim 2 should read as follows:

2. The process of claim 1 in which the concentration of antiblockingagent is sufficiently high to prevent congealing of the wax powder.

Signed and sealed this I 8th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GO'ITSCHALK 'Attesting Officer Commissionerof Patents FORM Po-105o (10-69) USCOMM-DC 60376-969 Q u 5 GOVERNMENTPRINTING I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION patent3,6 +,l30 Dated February 22, 1972 t Robert R. 'Evans and Peter S.Backlund It is certified that'error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Claim 2 should read as follows:

2. The process of claim 1 in which the concentration I of antiblockingagent is sufficiently high to prevent congealing of the wax powder.

Signed and sealed this 1 8th day of July 1972.

(SEAL) Attest;

EDWARD M.FLETGHER,JR. ROBERT GOT'ISCHALK Attesting Officer Commissionerof vPatents FORM PO-1050 (10-69) USCOMM-DC seam-Pee U 5. GOVIRNMENTFRINTING OFHCK: I95 J5"J" UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent 3,6'+ +,l30 Da ed February 22, 1972' Robert R. Evansand Peter S. Backlund It is certified that'error appears in theabove-identified patent and that saidLetters Patent are hereby correctedas shown below:

Claim 2 should read as follows:

2. The process of claim 1 in which the concentration of antiblockingagent is sufficiently high to prevent congealing of the wax powder.

Signed and sealed this 1 8th day of July 1972.

(SEAL) Attest;

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK 'Attesting Officer Commissionerof Patents FORM Po-1o50 (o-s9) USCOMM-DC scam-mac n U 5. GOVERNMENTPRINYING OFFICE: I959 O--J6-3!l

2. The process of claim 1 in which the concentration of antiblockingagent is sufficiently high to prevent congealing of the wax powder. 1 inwhich the concentration of antiblocking agent is sufficiently high toprevent congealin g of the wax powder.